Key for telephone-switchboards.



PATBNTBD OCT. 3, 1905.

P. H. LOVERIDGE. kKEY FOR TELEPHONE SWITGHBOARDS.

APPLICATION FILED DEU. l2, 1902.

V. .V 1 .k

UNITED STATES PATENT OFFICE.

FREIHCRICK H. LOVERIDCE, OF CHICAGO, ILLINOIS, ASSICNOR 'lO WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A COR- PORATION or ILLINOIS.

KEY FOR TELEPHONE-SWITCHBOARDS.

Specification of Letters Patent.

Patented Oct. 3, 1905.

Application filed December l2, 1902. Serial No. 134,941.

1" (1,7/7 11171/0711, it Tula/y cm2/cent:

Beit known that I, FREDERICK H. LovE- RIDGE, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Keys for Telephone- Switchboards, of which the following is a full, clear, concise, and exact description.

My invention relates to a switch-key, and has for its object more particularly to provide an improved structure which will be especially adapted for use as a party-line ringingkey to be mounted in the horizontal keyshelf of a telephone-switchboard.

One form of ringing-key which has heretofore been largely used in telephone-switchboards has been constructed with verticallymovable plungers which carry wedges for the actuation of the switch-springs and which are furnished with buttons on the top of the 'key-shelf, by which they may be depressed.

Switchboard-keys should be easy to manipulate, so that they will not unduly tire the operator; but an objection to the plunger-operated keys above mentioned has been that they are very liable to be accidentally actuated when struck by plugs which are withdrawn from the jacks by the operator and allowed to fall upon the key-shelf. Vhen a ringingkey of a coI'd-circuit over which conversation is being carried on is thus struck, a violent crack is produced in the telephones in the circuit, which is extremely disagreeable and interrupts the conversation. It has further been common to construct ringing-keys so that the particular plunger depressed will be held down by a magnet to apply the callingcurrent continuously until the called party answers, when the magnet is denergized and releases the plunger. Ringing-keys thus constructed have heretofore been somewhat bulky and the parts necessarily arranged so as not to be readily accessible for the purposes of inspection and repair. A further defect has been that it was not easy for the operator to see by looking down upon the key-shelf which of the several plungers of a party-line ringing-key had been depressed, and it is desirable that vthis should be apparent to the operator at a glance.

My invention was designed to provide a simple and extremely compact ringing-key in which these several defects of prior keys would be eliminated.

The principal characteristic of my key is that each set of switch-springs instead of being actuated by depressing a plunger is actuated instead by a cam rotatable upon a vertical axis, a crank-lever being provided upon the face of the key-shelf which may be turned to rotate said cam. Vith actuating mechanism of this character the keys will be unaffected by pressure on the top, as by plugs falling on them. They will be more easily operated than the old plunger-keys, and the operator can always tell at a glance which key has been actuated, because the cranklever will be turned to an angular position, thus serving, in effect, as a pointer.

In the preferred form of my invention the ringing-key comprises a number of vertical shafts mounted in a row in a suitable supporting-frame with the sets of switch-springs mounted parallel with the corresponding shafts, said springs being held edgewise in transverse vertical slots at the bottom of the frame and an actuating-cam carried by cach shaft to move the switch-springs when the shaft is rotated. I further preferably add a sticking-magnet, which may be constructed with a single elongated coil of wire wound in a core of E-shaped cross-section, said core thus presenting three polar faces, which lie alongside the row of shafts. Each shaft may then carry a vertical bar-armature which when the shaft is rotated will be swung laterally over against the magnet-poles, whereby the key will be held in its actuated position during the excitation of the magnet.

I will describe my invention particularly by reference to the accompanying drawings, which illustrate a key constructed in accordance therewith, and the features or combinations which I regard as novel will be set forth in the appended claims.

Figure 1 is a view of the key in elevation. Fig. 2 is a plan view thereof. Fig. 3 is a sectional view on line 3 3 of I. Fig. 4L is an end view, and Fig. 5 is a view in crosssection on line 5 5 of Fig. l.

The same letters of reference are used to designate the same parts wherever they are shown.

The key illustrated is a party-line ringingkey having [ive sets of switch-springs for applying specialized ringing-current to selectively operate the substation call-bells of telephone-lines, the key beingI intended to be mounted in the horizontal key-shelf of the central-oiice switchboard in association with an operators plug-circuit. Five actuatingshafts fr. fr are therefore shown mounted vertically to rock in bearings in the framework each shaft carrying at the top above the face of the supporting-frame a iin-shaped crank-lever which is adapted to be pulled by the iinger of the operator, as shown in Figs. l and 2, to rotate the shaft.

Each shaft a carries an insulating campiece a' to actuate a corresponding set of switch-springs c when the shaft is rotated. The shafts are mounted at intervals in a line along' the framework, and the corresponding sets of switch-springs are preferably held edgewise in the transverse vertical slots of an insulating supporting-strip (Z, extending longitudnally along the bottom of the frame and forming a part thereof. Theswiteh-springs of each set are thus held at the bottom in the slots of said strip and project upward alongside the corresponding shaft and substantially parallel therewith. The spring nearest the shaft normally rests upon a Hat portion of the cam-piece a, carried by the shaft, and when the shaft is rotated the corner of said campiece pushes this spring over in the direction of the general longitudinal axis of the structure. In the key shown each set of switch-springs comprises two movable strips and two other strips carrying contact-anvils therefor. Normally the strips are separated from their eontact-anvils; but when the shaft is rotated the cam a shifts the movable strips (which Aare arranged to move together by means of an interposed insulating-stud e) into contact with the anvils carried by the other strips. Each strip is suitably insulated from its neighbor.

The sticking-magnet is mounted alongside the row of actuating-shafts. This magnet may be constructed with a single coil of wire fia, disposed within the core m, of E-shaped cross-section, as shown in Fig. 5. Each shaft may be provided with an armature-bar f, earried thereby on the other side of said shaft 'from the switch-springs c vin such position that when the shaftis rotated to actuate the switchsprings the armature-bar will be swung laterally over against the polar faces of the magnet. In accordance with a well-known system the magnet will be energized until the called subscriber answers, so that the key once actuated will be held over to apply the ringingcurrent continuously until the called party shall respond, after which the magnet will be deenergized and permit the shaft to return to its normal position, which it will do by reason of the elasticity of the switch-springs bearing upon the cam-piece ce'.

It is desirable that party-line ringing-keys should have, in addition to the individual switch-springs which apply the specialized current, certain other switch-springs serving, for example, to interrupt the cord-circuit to be actuated in the actuationof any one of thc individual switches which control the application of the specialized ringing-current, and I have therefore provided such general springs inmy key to be actuated through the agency of a longitudinally-slidingl rod ,r/ whenever any one of the shafts (t is rotated. Said rod carries pins y', which project in position to be engaged by the several cam-pieces ft of the key-shafts, so that when any one of said keyshafts is turned the rod f/ will be moved longitudinally. This rod may carry pieces ,rfi f/ of insulating material arranged to actuate the sets of switch-springs /t /1.', which may be mounted in slots in the insulatingsupporting-strip (l in a manner similar to the mounting of the individual sets of switch-springs c c.

It will be appreciated that the structure shown and described is extremely compact, so that it will take up very little space, either laterally or in depth, in the key-shelf. The keys while not liable to accidental operation will nevertheless be easy for the operator to manipulate, and when any key is actuated the crank-lever on the face of the board will serve as an indicator, so that the merest glance will show which key has been operated.

I claim- 1. A switch-key comprising a supportingframe, a vertical shaftmounted to rock in bearings in said frame, a crank-lever carried by the upper end of said shaft, a set of switchsprings mounted at the bottom of the frame and extending up alongside the shaft, substantially parallel therewith, a cam-piece carried by the shaft adapted to move the switchsprings when the shaft is rotated, an armature carried by the shaft, and a magnet having` a polar face at the side of said shaft adapted to engage and hold the armature when the shaft is turned, to hold the key in its actuated position.

2. A party-line ringing-key for the horizontal key-shelf of a telephone-exchange switchboard, comprising a supporting-frame, a series of actuating-shafts mounted vertically to rock in bearings in said frame, a horizontallyprojecting' crank-arm carried by each shaft above the supporting-frame, switch-springs mounted in association with each shaft, a part carried by each shaft in position to move the corresponding switch-springs when the shaft is rotated, an electromagnet having a polepiece extended alongside the row of actuatingshafts, and an armature carried by each shaft adapted to be moved against the face of the magnet-pole as the shaft is rocked, whereby the key may be held in its actuated position by the magnet.

3. A party-lineringing-key for telephone- IOO switchboards,comprising' a supportilig-frame, a row of vertical actuz'iting-shafts mounted to rock in bearings in the supporting'-frame, an insulating-strip along the bottom of the frame, said strip having transverse vertical slots at intervals between the actuating-shafts, sets of switch-springs held edgewise in said slots between the shafts and substantially parallel therewith, and a cam carried by each shaft, adapted when the shaftis rotated to move the corresponding switch-springs.

4f. A multiple key for telephone-switchboards comprising a su pporting-frame,a series of vertical shafts mounted to rockin bearings in said frame, each shaft having,l a crank-lever projecting horizontally therefrom above the top of the frame, an insulating-strip along the bottom of the frame, transverse vertical slots in said strip adjacent to the several shafts` sets of switch-springs held edgewise in said slots, each set extending up alongside the corresponding1 shaft, a cam carried by each shaft in position to move the associated switchsprings when the shaft is rotated, a magnet having` polar faces extended longitudinally alongside the several shafts, and a vertical armature-bar carried by each shaft on the opposite side thereof 'from the switch-springs. adapted when the shaft is rotated to engage the polar faces of the magnet, whereby any key when once actuated may be held over by the magnet.

5. A switch-key for telephone-exchange switchboards comprising' a supporting-frame, a vertical shaft mounted to rock in bearings in said frame, a crank-lever carried by the shaft above the supporting-frame, switchsprings supported by the frame, a cam carried by the shaft adapted when the same is rocked to move said switch-sprinos`r and a magnetic lock adapted when the shaft is rocked to hold the same in such position.

6. A switch-key for a telephone-switchboard comprisingl a supporting-frame, anactuatingshaft mounted vertically to rock in bearings in said frame, a horiZontally-projecting crankarm carried by the shaft above the frame, an insulating-strip alongI the bottom of the frame, switch-springs supported by said strip, a cam carried by the shaft adapted when the same is rocked to actuate the switch-springs, an armature carried by the shaft, and a mag'nethaving a polar face adapted to engage and hold the armature when the shaft is turned to lock the shaft in such position.

7. A switch-key for a telephone-exchange comprising asupporting-frame, an actuating'- sha'ft mounted to rock in bearings in said frame. a horizontally-projecting crank-arm carried by the shaft above the supportingframe, an insulating-strip alone,l the bottom of the frame, said strip having' slots therein adjacent to said shaft, switch-springs held in said slots parallel to said shaft, a cam carried by thc shaft adapted when the shaft is rocked to actuate said springs, an armature carried by the shaft, and a magnet havingl a polar face at the side of said shaft adapted to engage and hold the armature when the shaft is turned to lock the shaft in its actuated position.

VIn witness whereof l hereunto subscribe my name this 10th day of November, A. l). 1909.

FREDERICK H. LOVERIDGE. lVitnesses:

( n n'rn'Un u Ers'r en, EDWIN H. SMY'run. 

